1

从未尝试过使用 Windows 窗体进行异步调用。我不能使用新的aynch/await，因为我没有最近的 Visual Studio/.NET。我需要的是“执行请求长时间的操作（填充 IList）”，当它完成后，在 TextBox 上写入该列表的结果。

在 Internet 上搜索，我发现这个示例似乎可行，但在我看来也符合要求（也许有些东西既快速又简单）：

private void button1_Click(object sender, EventArgs e)
{
    MyTaskAsync();
}

private void MyTaskWorker()
{
    // here I populate the list. I emulate this with a sleep of 3 seconds
    Thread.Sleep(3000);
}

private delegate void MyTaskWorkerDelegate();

public void MyTaskAsync()
{
    MyTaskWorkerDelegate worker = new MyTaskWorkerDelegate(MyTaskWorker);
    AsyncCallback completedCallback = new AsyncCallback(MyTaskCompletedCallback);

    AsyncOperation async = AsyncOperationManager.CreateOperation(null);
    worker.BeginInvoke(completedCallback, async);
}

private void MyTaskCompletedCallback(IAsyncResult ar)
{
    MyTaskWorkerDelegate worker = (MyTaskWorkerDelegate)((AsyncResult)ar).AsyncDelegate;
    AsyncOperation async = (AsyncOperation)ar.AsyncState;

    worker.EndInvoke(ar);

    AsyncCompletedEventArgs completedArgs = new AsyncCompletedEventArgs(null, false, null);
    async.PostOperationCompleted(delegate(object e) { OnMyTaskCompleted((AsyncCompletedEventArgs)e); }, completedArgs);
}

public event AsyncCompletedEventHandler MyTaskCompleted;

protected virtual void OnMyTaskCompleted(AsyncCompletedEventArgs e)
{
    if (MyTaskCompleted != null)
        MyTaskCompleted(this, e);

    // here I'll populate the textbox
    textBox1.Text = "... content of the Iteration on the List...";
}

对于这个简单的操作，我真的需要 50 行代码吗？或者我可以删除一些东西？我只需要一个简单的异步调用->完成后的回调。

没有锁，根本没有并发......

4

2 回答 2

2

您可以将 TPL 与 C# 4.0 一起使用，如下所示：

private void button1_Click(object sender, EventArgs e)
{
    Task.Factory.StartNew(() => DoWork())
        .ContinueWith(t => UpdateUIWithResults(t.Result)
        , CancellationToken.None
        , TaskContinuationOptions.None
        , TaskScheduler.FromCurrentSynchronizationContext());
}

这从DoWork线程池线程开始，允许它在 UI 线程之外进行处理，然后UpdateUIWithResults在 UI 线程中运行，将DoWork.

于 2013-04-17T15:41:12.637 回答
0

您可以使用Task.Factory.StartNew将工作推送到线程池。Task.ContinueWith会给你一个“完成的回调”。

private void button1_Click(object sender, EventArgs e)
{
    var ui = TaskScheduler.FromCurrentSynchronizationContext();
    Task<List<T>> task = Task.Factory.StartNew(() => MyTaskWorker());
    task.ContinueWith(t => OnMyTaskCompleted(t), ui);
}

private List<T> MyTaskWorker()
{
    // here I populate the list. I emulate this with a sleep of 3 seconds
    Thread.Sleep(3000);
    return ...;
}

protected virtual void OnMyTaskCompleted(Task t)
{
    // here I'll populate the textbox with t.Result
    textBox1.Text = "... content of the Iteration on the List...";
}
于 2013-04-17T15:40:31.687 回答